package com.hmdp.service.impl;

import com.baomidou.mybatisplus.extension.service.IService;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisWorker redisWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private BlockingQueue<VoucherOrder>orderTasks = new ArrayBlockingQueue<>(1024*1024);

    private static final ExecutorService SECKILL_ORDER_EXECUTOP = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){  //当前类初始化完毕就执行
        SECKILL_ORDER_EXECUTOP.submit(new VoucherorderHandler());
    }
    private class VoucherorderHandler implements Runnable{

        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();

                    //创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                   log.error("处理订单异常");
                }
            }
        }
    }

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //订单处理
    private void handleVoucherOrder(VoucherOrder voucherOrder){
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //获取锁之后，在获取代理对象
        if(!isLock){
            //获取失败,返回错误或重试
           log.error("不允许重复下单");
           return;
        }
        try{
             proxy.creatVouncherOrder(voucherOrder);
        }finally {
            lock.unlock();
        }

    }
    //代理对象
    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userid = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userid.toString()
        );
        //2.判断是否为0
        int r = result.intValue();
        if(r!=0){
            //2.1 1表示没有资格
            return Result.fail(r==1 ? "库存不足" : "不能重复下单");
        }
        long orderId = redisWorker.nextId("order");
        //2.2 0表示有资格,把下单信息保存到阻塞队列里面
        //创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //订单id
        voucherOrder.setId(orderId);
        //用户id
        voucherOrder.setUserId(userid);
        //代金券id
        voucherOrder.setVoucherId(voucherId);
        //放入阻塞队列
        orderTasks.add(voucherOrder);

        //获得代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //TODO 保存阻塞队列

        //3.返回订单id
        return Result.ok(orderId);
        //拿到事务代理对象(事务)，完整整个事务之后再释放锁
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀尚未开始!");
//        }
//        //判断秒杀是否结束
//        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已经结束!");
//        }
//        //3.判断库存是否充足
//        if(voucher.getStock()<1){
//            return Result.fail("库存不足！");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
//        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        //获取锁之后，在获取代理对象
//        if(!isLock){
//            //获取失败,返回错误或重试
//            return Result.fail("一个人只允许下一单");
//        }
//        try{
//            //拿到事务代理对象(事务)，完整整个事务之后再释放锁
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
//            return proxy.creatVouncherOrder(voucherId);
//        }finally {
//            lock.unlock();
//        }
//
//
//    }

    @Transactional
    public void creatVouncherOrder(VoucherOrder voucherOrder) {
            //一人一单判断
            Long userId = voucherOrder.getId();
           //保证用户id的值一样，获得的锁就一样
            //查询订单
            int count =Math.toIntExact(query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count());
            if (count > 0) {
                //用户已经购买过了
                log.error("用户不得重复购买");
                return ;
            }
            //扣减库存
            boolean success = seckillVoucherService.update().setSql("stock=stock-1")  //set stock = stock-1
                    .gt("stock", 0)   //where stock = ?
                    .eq("voucher_id", voucherOrder.getVoucherId()).update();  //where id = ?
            if (!success) {
                log.error("库存不足");
                return;
            }
            save(voucherOrder);
        }

}
